With the advent of high fuel prices, the automotive industry has reacted with a selection of Electric Vehicles (EVs). Such EVs are propelled by an electric motor (or motors) that are powered by rechargeable power sources (e.g., battery packs). EVs include both full electric and hybrid electric vehicles. Electric motors have several advantages over internal combustion engines. For example, electric motors may convert about 75% of the chemical energy from the batteries to power the wheels, whereas internal combustion engines (ICES) may only convert only about 20% of the energy stored in gasoline. EVs emit no tailpipe pollutants when operating in battery mode, although the power plant producing the electricity may emit them. Electric motors provide quiet, smooth operation, strong acceleration and require relatively low maintenance. However, most EVs can only go about 100-200 miles before requiring recharging. Fully recharging an EV's battery pack may take about 4 to 8 hours. Even a quick charge to about 80% capacity can take about 30 minutes. Furthermore, as battery pack size increases, so does the corresponding charging time. EV charging may take place at the owner's residence using an electric vehicle recharging station, referred to herein as an electric vehicle supply equipment (EVSE).
Such EVSEs are typically installed at the residence (e.g., in a garage), and are electrically coupled to the electrical load center for the residence. For example, the EVSE may be coupled by an electrical conduit to a branch circuit breaker of the load center by either being wired directly or plugged into a wall socket. During such EV charging events, the current draw may be quite substantial. In such cases where other residential electric components are also being operated (e.g., aft conditioning units, hot water heaters, fans, lighting, electric stoves, electric dryers, motors, etc.) the overall power consumption requirements may, in some instances, exceed the maximum amperage rating of the utility service to the residence. Such electrical utility services typically have maximum ratings that range from about 60 A-200 A. In such overdraw situations where the maximum rating is exceeded, a main breaker protecting the load center may be actuated (e.g., tripped) to protect the residence from a possible over-current situation.
Therefore, there is a need for improvements to systems, such as residential electrical systems including load centers having EVSEs electrically connected to them.